Hypodermic syringe with radially movable blocking elements

ABSTRACT

A hypodermic syringe comprising a liquid container and a needle connected thereto at one end, which assembly is incorporated in a housing, the liquid container being bounded at the other end by a piston, and an operating mechanism being present to exert a force on the piston, one or more blocking elements being present for locking the operating mechanism or the piston against movement relative to the liquid container, the housing showing a diameter transition such that when the blocking elements pass along it, they are moved radially so that the blocking is removed and the piston penetrates into the liquid container so that the liquid flows out through the needle.

United States Patent 1 Post et al.

[ I-IYPODERMIC SYRINGE WITH RADIALLY MOVABLE BLOCKING ELEMENTS [75]Inventors: Hendrik Alle Post; Daniel Ong, both of Emmasingel, Eindhoven,

Netherlands [73] Ass ignee: U.S. Philips Corporation, New York,

[22] Filed: Aug. 10, 1970 [21] Appl. No.: 62,332

[30] Foreign Application Priority Data Aug. 25, 1969 Netherlands 6912969[52] US. Cl. 128/218 F, 128/215, 128/218 D, 128/218 P [51] Int. Cl A6lm5/20 [58] Field of Search 128/2-18 R, 218 F, 128/218 A, 218 D, 218 P,218 PA, 218 DA,

[56] References Cited UNlTED STATES PATENTS 3,055,362 9/1962Uytenbogaart 128/218 F 2,752,918 ,7/1956 Uytenbogaart 128/218 F [451July 3,1973

Primary ExaminerRic hard A. Gaudet Assistant Examiner-J. C. McGowanAtt0rneyFrank R. Trifari [57] ABSTRACT A hypodermic syringe comprising aliquid container and a needle connected thereto at one end, whichassembly is incorporated in a housing, the liquid con tainer beingbounded at the other end by a piston, and an operating mechanism beingpresent to exert a force on the piston, one or more blocking elementsbeing present for locking the operating mechanism or the piston againstmovement relative to the liquid container, the housing showing adiameter transition such that when the blocking elements pass along it,they are moved radially so that the blocking is removed and the pistonpenetrates into the liquid container so that the liquid flows outthrough the needle.

4 Claims, 3 Drawing Figures PATENTEI] JUL 3 1973 saw 1 or I NVE N TORS'HENDRIK ALLE POST DANIEL ONG L Lw [d AGENT ig-Ml HYPODERMIC SYRINGE WITHRADIALLY MOVABLE BLOCKING ELEMENTS The invention relates to a hypodermicsyringe comprising an assembly of liquid container and a needleconnected thereto at one end, which assembly is incorporated in anelongate housing so as to be movable, the other end being bounded by apiston fitting in said container, the housing being bounded on the sideof the needle by a wall through which the needle can, but the liquidcontainer cannot, pass, an operating mechanism being furthermore presentto exert a force on the piston.

A hypodermic syringe of the above-described type is known from theFrench Pat. specification No. 1,342,358. In this hypodermic syringe apressure is exerted on the piston by means of a pre-tensioned springafter unlocking the operating mechanism. As a result of this, theassembly of liquid container and needle is moved to the outside while atthe same time :1 diaphragm which separates the liquid from the needlecan be broken in that the liquid becomes under pressure so that theliquid starts flowing out.

A drawback of this known hypodermic syringe is that the liquid canalready be pressed out of the liquid container before the needle haspenetrated sufficiently far into the part of the body to be treated.

It is the object of the invention to mitigate this drawback and toprovide a hypodermic syringe in which the instant at which thepressing-out of the liquid out of the liquid container begins isdetermined unambiguously by the construction of the syringe.

In order to realize the end in view, the hypodermic syringe according tothe invention is characterized in that one or more blocking elements arepresent which can be moved at right angles to the longitudinal directionof the housing and which block the operating mechanism or the pistonagainst movement relative to the'liquid container, the wall of thehousing showing, at least over those parts of its circumference overwhich the blocking elements extend, a diameter transition which issituated at a distance from the upper edge of the liquid contained atmost corresponding to the length of the needle, all this in such mannerthat in passing said transition the said elements move radially and theblocking is removed, after which the piston can penetrate into theliquid container and the liquid flows out through the needle.

Upon exerting a force by the operating mechanism in the hypodermicsyringe according to the invention, first the assembly of liquidcontainer and needle is moved over such a distance that the needle hasreached the desirable depth of penetration, after which, when thetransition edge provided in the housing is passed, the blocking isremoved and the piston presses the liquid out of the liquid containernlnthis manner the instant of flowing-out of the liquid is fully determinedby the design of the housing.

The blocking elements may have a variety of constructions; one exampleis constituted by pawl segments incorporated in a groove of the pistonor a pressure member cooperating therewith, said pawl segments beingforced by springs against the wall of the housing, their configurationbeing such that upon passing the diameter transition they are forcedinwards over such a distance that they become located inside the wall ofthe liquid container.

In a favorable embodiment of the hypodermic syringe according to theinvention the blocking elements are formed by annular segments bearingindividually on the upper edge of the liquid container and engaging withtheir outer annular surface the wall of the housing, the inner annularsurface of said segments being at least partly bevelled and having asmallest diameter smaller than the inside diameter of the liquidcontainer, the piston and a pressure member, respectively, cooperatingtherewith of the operating mechanism comprising a bevelled surface whichbears against the bevelled surface of the annular segments, the diameterat the said diameter transition becoming larger so that the annularsegments can move outwards and are released from the piston and thepressure member, respectively.

In a further favorable embodiment of the hypodermic syringe according tothe invention the blocking elements are constituted by outwardlyspringing lugs which are connected to the piston or a pressure membercooperating therewith and which face the liquid container with theirfree end and in the untensioned condition have a larger diameter thanthe wall of the liquid container, the piston and the pressure member,respectively, having space for receiving said lugs when they arecompressed, said lugs comprising, on their surface bearing on the edgeof the liquid container, a collar which falls within the liquidcontainer and comprising a bevel on their side facing the inner wall ofthe housing, the diameter of the housing at the area of the saiddiameter transition becoming smaller so that when the lugs move alongsaid transition they are forced inwards.

In another favorable embodiment of the hypodermic syringe according tothe invention the blocking elements are likewise formed by outwardlyspringing lugs connected to the piston or the pressure member, but inthis embodiment their free end is remote from the liquid container andwhich lugs, in the untensioned condition, have a larger diameter thanthe wall of the liquid container, the piston and the pressure member,respectively, having space for receiving said lugs when they arecompressed, said lugs comprising a surface which bears on the edge ofthe liquid container, the part of .the lugs situated between saidsurface and their free end being bevelled on the side facing the wall ofthe housing, the diameter of the housing at the area of the saiddiameter transition becoming smaller so that when said lugs are movedalong it they are forced inwards.

In the two last-mentioned embodiments the pressure member and the pistonand the lugs connected thereto, respectively, may be formed as oneassembly, for example, of a synthetic resin.

In order that the invention may be readily carried into effect, it willnow be described in greater detail, by way of example, with reference tothe accompanying drawings, in which FIG. 1 diagrammatically shows ahypodermic syringe comprising a pressure member provided with blockinglugs.

FIG. 2 diagrammatically shows a hypodermic syringe in which the pistonis provided with blocking lugs which with their free ends are remotefrom the liquid container.

FIG. 3 diagrammatically shows a hypodermic syringe which comprisesseparate blocking segments which can be moved radially. V

Reference numeral 1 in FIG. 1 denotes a housing which is constructed oftwo parts 2 and 3. An assembly of liquid container 4 and needle 5connected thereto is arranged in said housing so as to be movable. Thelower side of the liquid container 4 is closed by a diaphragm 6 whichbursts when the liquid comes under pressure. The upper side of theliquid container is closed by a piston 7. A pressure member 8constructed as a cup spring cooperates with the piston 7. A compressionspring 9 is present between the pressure member 8 and the upper side ofthe part 3 of the housing. The pressure member 8 is locked againstmovement by means of a locking member 10 which is connected thereto andwhich comprises legs 1 l on its upper side. On their outside the legs 11comprise a bevel 12 which bears on an edge of the part 3 of the housingwith flat sides 13.

A slidable sleeve 14 which comprises a conical bore 15 which cancooperate with the bevel 12 of the legs 11 is situated around the part 3of the housing. Inorder to prevent an unintentional actuation of thesyringe a pin 16 is present which projects in the space between the legs11 in such manner that said legs cannot be compressed. The pin 16 isaffixed to a cap 17 with which the pin can be removed.

The pressure member 8 comprises resilient lugs 20 which bear on theupper edge of the liquid container 4 with their free end 21. The freeend 21 comprises a collar 22 which falls within the liquid container.From the free end 21 the lugs'have a bevel 23. At the area of the lugs20 the part 3 of the housing comprises axial grooves in which the lugs20 are situated. These grooves extend up to the position 24 where theychange to a smaller diameter via a bevel 50.

The operation of this hypodermic syringe is as follows: First of all thecap 17 with pin 16 is removed. The

' housing 14 is then moved downwards relative to the part 3 of thehousing, the legs 11 being squeezed by conical bore 15 so that the edges13 are released and the member 10 with pressure member 8 is forceddownwards by the spring 9. Since the pressure member 8 presses on theliquid container 4 by means of the lugs 20, said container is also moveddownwards, the needle 5 penetrating the wall of the housing. At theinstant, the needle has substantially entirely left the housing, thelugs 20 pass the diameter transition 24. Said lugs 20 are forced inwardsso that they are released from the edge of the liquid container 4, andthe pressure member forces the piston 7 downwards and the liquid ispressed out of the liquid container. During the lowering of the liquidcontainer 4 by means of the pressure member 8, the lugs 20 exert noextra frictional force on the wall of the part 3 of the housing becausethe lugs 20 with collar 22 engage behind the edge of the liquidcontainer 4 so that the lugs 20 cannot move outwards.

In this manner a hypodermic syringe is obtained in which the instant atwhich the pressing-out of liquid begins is determined unambiguously bythe position of the diameter transition bevel 50.

A seal 25 is present between the liquidcontainer 4 and the part 2 of thehousing, so that prior to use the compartment 26 in which the needle 5is present is fully closed so that the needle can be stored in a sterileatmosphere.

FIG. 2 shows a hypodermic syringe which corresponds in general with thesyringe shown in FIG. 1 and in which therefore corresponding componentsare referred to by the same reference numerals. The difference from thesyringe shown in FIG. 1 is that the piston 7 is provided with lugs 30which are remote from the liquid container with their free end. Ahorizontal surface 31 of each of said lugs 30 bears on the edge of theliquid container 4, while from said surface the lugs 30 extend upwardsat an angle over a part 32. The pressure member 8 is constructed so thatit bears again against the piston 7 and is furthermore provided withrecesses in which the lugs 30 will bear upon compression, In this mannerit is achieved that when the operating mechanism is actuated first thewhole assembly of liquid container 4 and needle 5 is moved. When thebevel 50 of the grooves are passed, the lugs 30 are pressed inwards sothat the piston 7 in the liquid container starts moving and the liquidis pressed out.

FIG. 3 shows again a hypodermic syringe as is shown in FIGS. 1 and 2 inwhich the blocking elements are formed by separate annular segments 40 ahorizontal surface 41 of which bears on the edge of the liquid container4. The outer annular surface of said segments bears against the innerwall of the part 3 of the housing, while the inner annular surface isprovided with an inclined part 42 which has a smaller diameter than theinside diameter of the liquid container. The pressure member 8 has adiameter which is slightly smaller than that of the liquid containerand, with a bevelled surface 43, engages the surface 42 of the annularsegments. At the area 24 the part 3 of the housing changes into the part2 of the housing which has a slightly larger diameter. When actuatingthe operating mechanism of this syringe also, first the liquid containerand the needle are moved by means of the pressure member because theannular segments lock the pressure member and the liquid container. Whenthe annular segments 40 pass the edge 24 they are forced outwards as aresult of the forces exerted on the inclined surface 42 so that they arereleased from the pressure member. The pressure member then presses onthe piston so that the liquid starts flowing out.

From the above it may be obvious that the invention provides ahypodermic syringe in which the sequence of movement of the liquidcontainer with needle and piston is entirely determined by the design ofthe housing and blocking elements cooperating therewith.

What is claimed is:

l. A hypodermic syringe comprising a cylindrical liquid container, aneedle connected to one end thereof, a piston slidably fitting in theother end ofthe liquid container, a medicament in the container betweenthe needle and piston, an elongate cylindrical housing slidably carryingsaid container, a pressure member slidably positioned in the housingadjacent the piston end of the container, transversely movable positiveblocking means engaging the edge of the container at the piston end andcontrolling relative movement of the container and the piston therein bythe pressure member, spring means for forcing the pressure member towardthe needle end of the housing, stop means on the needle end of thehousing, transition means on the inner surface of the housingbetweensaid blocking means and said stop means for causing the blockingmeans to move out of engagement with the container whereby the pressuremember will force the piston toward the needle to eject the medicamentin said container.

2. The invention as set forth in claim 1 and wherein the pressure memberhas a head portion sized to slidably fit within the container, thehousing comprises an upper portion and a lower portion of larger innerdiameter and further wherein the transversely movable positive blockingmeans comprises annular elements bearing on the edge of the cylindricalcontainer at the piston end and in engagement with the inner wall of theupper portion of the housing, the inner face of each annular elementsloping downwardly and inwardly and terminating inwardly of thecontainer wall to form a circular opening of smaller diameter than thehead portion of the pressure member, the head portion of said pressuremember engaging said inner faces whereupon movement of the pressure headmoves the cylindrical container toward the lower housing portion, uponreaching the lower housing portion the pressure head portion forces theblocking elements outwardly to allow the pressure head to engage thepiston and upon continued movement eject the medicament from thecontainer.

3. The invention as set forth in claim 1 and wherein the housingcomprises an upper portion and a lower portion, said lower portionhaving a plurality of axial grooves in its inner wall, the transverselymovable positive blocking means comprising a plurality of lugs extendingradially from the pressure member and fitting in the aforesaid grooves,said lugs each having a flat lower face engaging the edge of thecontainer adjacent the piston end and a downwardly and inwardly slopingouter face, the lower end of each of the grooves being provided with aninwardly and downwardly sloping bevel termination, whereupon downwardmovement of the pressure head the outer faces of the lugs engage thebevel terminations and cause the lugs to move inwardly so as to forcethe flat lower faces of the lugs off the container edge and allow thelugs to be forced radially inwardly to slide within the container andengage the piston to eject the medicament.

4. The invention as set forth in claim 1 and wherein the housingcomprises an upper portion and a lower portion having a plurality ofaxial grooves in its inner wall, the transversely movable positiveblocking means comprising a plurality of lugs connected to the pistonand fitting in the aforesaid grooves, each lug having an intermediatehorizontal flat face engaging the edge of the container adjacent thepiston end, the upper portion of each lug extending into its respectivegroove,

the lower end of each of the grooves being provided with an inwardly anddownwardly sloping bevel termination, whereupon downward movement of thepressure member the upper portion of the lugs will engage the bevelterminations and be forced inwardly removing theflat face lug portionfrom the edge of the con tainer and allowing the piston to then be movedto eject the medicament.

1. A hypodermic syringe comprising a cylindrical liquid container, aneedle connected to one end thereof, a piston slidably fitting in theother end of the liquid container, a medicament in the container betweenthe needle and piston, an elongate cylindrical housing slidably carryingsaid container, a pressure member slidably positioned in the housingadjacent the piston end of the container, transversely movable positiveblocking means engaging the edge of the container at the piston end andcontrolling relative movement of the container and the piston therein bythe pressure member, spring means for forcing the pressure member towardthe needle end of the housing, stop means on the needle end of thehousing, transition means on the inner surface of the housing betweensaid blocking means and said stop means for causing the blocking meansto move out of engagement with the container whereby the pressure memberwill force the piston toward the needle to eject the medicament in saidcontainer.
 2. The invention as set forth in claim 1 and wherein thepressure member has a head portion sized to slidably fit within thecontainer, the housing comprises an upper portion and a lower portion oflarger inner diameter and further wherein the transversely movablepositive blocking means comprises annular elements bearing on the edgeof the cylindrical container at the piston end and in engagement withthe inner wall of the upper portion of the housing, the inner face ofeach annular element sloping downwardly and inwardly and terminatinginwardly of the container wall to form a circular opening of smallerdiameter than the head portion of the pressure member, the head portionof said pressure member engaging said inner faces whereupon movement ofthe pressure head moves the cylindrical container toward the lowerhousing portion, upon reaching the lower housing portion the pressurehead portion forces the blocking elements outwardly to allow thepressure head to engage the piston and upon conTinued movement eject themedicament from the container.
 3. The invention as set forth in claim 1and wherein the housing comprises an upper portion and a lower portion,said lower portion having a plurality of axial grooves in its innerwall, the transversely movable positive blocking means comprising aplurality of lugs extending radially from the pressure member andfitting in the aforesaid grooves, said lugs each having a flat lowerface engaging the edge of the container adjacent the piston end and adownwardly and inwardly sloping outer face, the lower end of each of thegrooves being provided with an inwardly and downwardly sloping beveltermination, whereupon downward movement of the pressure head the outerfaces of the lugs engage the bevel terminations and cause the lugs tomove inwardly so as to force the flat lower faces of the lugs off thecontainer edge and allow the lugs to be forced radially inwardly toslide within the container and engage the piston to eject themedicament.
 4. The invention as set forth in claim 1 and wherein thehousing comprises an upper portion and a lower portion having aplurality of axial grooves in its inner wall, the transversely movablepositive blocking means comprising a plurality of lugs connected to thepiston and fitting in the aforesaid grooves, each lug having anintermediate horizontal flat face engaging the edge of the containeradjacent the piston end, the upper portion of each lug extending intoits respective groove, the lower end of each of the grooves beingprovided with an inwardly and downwardly sloping bevel termination,whereupon downward movement of the pressure member the upper portion ofthe lugs will engage the bevel terminations and be forced inwardlyremoving the flat face lug portion from the edge of the container andallowing the piston to then be moved to eject the medicament.